Risk factors for nephrolithiasis in children

The aim of this study is to evaluate the clinical outcome in children with urinary calculi, to detect risk factors for nephrolithiasis in childhood. This retrospective study comprised 62 pediatric nephrolithiasis patients who have come for routine follow-up visits between the dates of January 2002-August 2006 (48% girls and 52% boys). The mean age of the patients was 8.8 +/- 4.5 years (1-16 years). Hypercalciuria was found in 25 (40%) patients. The mean urinary calcium excretion for hypercalciuric patients was 5.7 +/- 1.2 mg/kg (4.8 mg/kg per day). In our hypercalciuric patients 15 (60%) children had abdominal or flank pain, seven (28%) patients macroscopic hematuria and three (12%) dysuria. Hypocitraturia is the second important risk factor for nephrolithiasis. Urinary calcium excretion showed a positive correlation with the stone size (r = 0.482, P = 0.043). A positive correlation was found between recurrent urinary tract infection (UTI) and hypercalciuria (r = 0.528, P = 0.017). Urinary citrate excretion showed a negative correlation with recurrent UTI (r = -0.503, P = 0.024). Hyperuricaciduria, hyperoxaluria were found to have no effect on the stone size and UTI of the patients. Stones were disintegrated with ESWL in two patients, endoscopic interventions were used in one patient and two underwent an open surgical procedure. All children with nephrolithiasis should have a metabolic screen. Children with a positive family history and consanguinity should be followed carefully with respect to metabolic abnormalities.